Publications by authors named "Maarten Spruit"

27 Publications

  • Page 1 of 1

Good results at 2-year follow-up of a custom-made triflange acetabular component for large acetabular defects and pelvic discontinuity: a prospective case series of 50 hips.

Acta Orthop 2021 Feb 15:1-7. Epub 2021 Feb 15.

Orthopaedic Department, Sint Maartenskliniek, Nijmegen.

Background and purpose - Custom triflange acetabular components (CTACs) are suggested as good solutions for large acetabular defects in revision total hip arthroplasty. However, high complication rates have been reported and most studies are of limited quality. This prospective study evaluates the performance of a CTAC in patients with large acetabular defects including pelvic discontinuity.Patients and methods - Prospectively collected data of 49 consecutive patients (50 hips), who underwent an acetabular revision with a CTAC were analyzed. Follow-up (FU) was 2 years. The median age of the patients was 68 years (41-89) and 41 were women. Primary outcomes were re-revision of the CTAC and differences between the modified Oxford Hip Score (mOHS) preoperatively and at 2-year follow-up. Secondary outcomes included several patient-reported outcomes (PROMs), radiological results, complications, and a comparison between hips with and without pelvic discontinuity (PD).Results - 1 patient (1 hip) was lost to the 2-year FU. No CTAC needed re-revision. The preoperative and 2-year FU mOHS were available in 40 hips and improved statistically significantly. All of the other secondary outcomes improved over time. 5 hips (of 45 with radiological 2-year FU) had loosening of screws. 8 hips had complications, including 3 persistent wound leakage, 3 pelvic fractures, and 1 dislocation. The mOHS and complication rate were similar in hips with and without PD.Interpretation - Reconstruction of large acetabular defects with and without PD with this CTAC showed good improvement in patient-reported daily functioning, high patient-reported satisfaction, few complications, and no re-revisions at 2-year FU.
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http://dx.doi.org/10.1080/17453674.2021.1885254DOI Listing
February 2021

Supine Traction Versus Prone Bending Radiographs for Assessing the Curve Flexibility in Spinal Deformity.

Global Spine J 2021 Jan 28:2192568220979136. Epub 2021 Jan 28.

Department of Research, 6033Sint Maartenskliniek, Nijmegen, the Netherlands.

Study Design: Retrospective cohort study.

Objectives: No consensus exists among surgeons on which radiologic method to prefer for the assessment of curve flexibility in spinal deformity. The objective of this study was to evaluate the difference in curve correction on supine traction radiographs versus prone side bending radiographs.

Methods: A retrospective analysis of idiopathic scoliosis (IS), degenerative idiopathic scoliosis (DIS) and de novo degenerative lumbar scoliosis (DNDLS) patients was performed on supine traction as well as prone bending films (when available). Age, weight, traction force, diagnosis and Cobb angles of the primary and secondary curves were extracted. Differences in curve correction (percentages) on traction versus prone bending radiographs were analyzed for the primary and secondary curve. Subgroup analyses were performed for the 3 different diagnoses.

Results: In total, 170 patients were eligible for inclusion. 43 were diagnosed with IS, 58 with DIS and 69 with DNDLS. For the primary curve, greater curve correction was obtained with bending in the DNDLS group ( < 0.001). In the DIS group, there was a trend toward more correction on bending ( = 0.054). In de IS group no difference was found. For the secondary curve, bending showed more curve correction in the IS and DIS group ( = 0.002 and <0.001). No difference was found in the DNDLS group.

Conclusion: Compared to traction radiographs, bending radiographs better serve the purpose of curve flexibility assessment of IS, DIS and DNDLS spinal deformity, despite the fact that patients are exposed to more radiation.
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http://dx.doi.org/10.1177/2192568220979136DOI Listing
January 2021

No added value of 2-year radiographic follow-up of fusion surgery for adolescent idiopathic scoliosis.

Eur Spine J 2021 Mar 3;30(3):759-767. Epub 2021 Jan 3.

Department of Orthopedics, Sint Maartenskliniek, Nijmegen, The Netherlands.

Purpose: For fusion surgery in adolescent idiopathic scoliosis (AIS) consensus exists that a 2-year radiographic follow-up assessment is needed. This standard lacks empirical evidence. The purpose of this study was to investigate the radiographic follow-up after corrective surgery in AIS, from pre-until 2 years postoperative.

Methods: In this historical cohort study, 63 patients surgically treated for AIS, age ≤ 25 years, with 2-year radiographic follow-up, were enrolled. The primary outcome measure was the major Cobb angle. Secondary outcomes were coronal and sagittal spino-pelvic parameters, including proximal junction kyphosis (PJK) and distal adding-on. Change over time was analyzed using a repeated measures ANOVA.

Results: The major curve Cobb angle showed a statistically significant change for pre- to 1 year postoperative, but not for 1- to 2-year follow-up. Seven out of 63 patients did show a change exceeding the error of measurement (5°) from 1- to 2-year follow-up (range -8° to +7°), of whom 2 patients showed curve progression and 5 showed improvement. PJK or distal adding-on was not observed.

Conclusions: No statistically significant changes in major curve Cobb angle were found during postsurgical follow-up, or in adjacent non-fused segments. The findings of this study are not supportive for routine radiographs 2 years after fusion surgery in AIS patients.
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http://dx.doi.org/10.1007/s00586-020-06696-xDOI Listing
March 2021

Mechanical Stability of the Prodisc-C Vivo Cervical Disc Arthroplasty: A Preliminary, Observational Study Using Radiostereometric Analysis.

Global Spine J 2020 May 23;10(3):294-302. Epub 2019 May 23.

Sint Maartenskliniek, Nijmegen, the Netherlands.

Study Design: Prospective cohort study.

Objective: To investigate the primary stability of the Prodisc-C Vivo cervical disc arthroplasty with regard to the adjacent cervical vertebrae using radiostereometric analysis (RSA), and to monitor its clinical performance.

Methods: Sixteen patients with degenerative cervical disc disease were included. RSA radiographs were obtained at the first postoperative day, at 6 weeks, 3 months, and 6 months postoperatively. Migration (translation [mm]) of the superior and inferior implant components were measured with model-based RSA, expressed along the 3 orthogonal axes, and calculated as total translation. Clinical outcomes were Neck Disability Index, numeric rating scales for neck and arm pain, Likert-type scales for satisfaction, and adverse events. Range of motion was reported as C2-C7 flexion-extension mobility (ROM).

Results: At final follow-up, no significant increase over time in median total translation was found. One inferior and 3 superior components subsided but were asymptomatic. ROM remained stable and clinical outcomes improved over time. Although 3 patients were unsatisfied and 3 adverse events occurred, this was not related to translation of the components.

Conclusions: On a group level, both components of the Prodisc-C Vivo cervical disc arthroplasty remained stable over time and below the clinical threshold of 1 mm. Individual outliers for translation were not clinically relevant and probably related to settling of the components into the vertebral endplates. RSA allowed us to perform a preliminary but accurate study on the micromotion of a new cervical disc replacement in a small sample size, without putting large numbers of patients at risk.
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http://dx.doi.org/10.1177/2192568219850763DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7160805PMC
May 2020

The Natural History of Progression in Adult Spinal Deformity: A Radiographic Analysis.

Global Spine J 2020 May 1;10(3):272-279. Epub 2019 May 1.

Sint Maartenskliniek, Department of Orthopaedic Surgery, Nijmegen, the Netherlands.

Study Design: Historical cohort study.

Objective: To evaluate progression in the coronal and sagittal planes in nonsurgical patients with adult spinal deformity (ASD).

Methods: A retrospective analysis of nonsurgical ASD patients between 2005 and 2017 was performed. Magnitude of the coronal and sagittal planes were compared on the day of presentation and at most recent follow-up. Previous reported prognostic factors for progression in the coronal plane, including the direction of scoliosis, curve magnitude, and the position of the intercrest line (passing through L4 or L5 vertebra), were studied.

Results: Fifty-eight patients were included with a mean follow-up of 59.8 ± 34.5 months. Progression in the coronal plane was seen in 72% of patients. Mean Cobb angle on the day of presentation and most recent follow-up was 37.2 ± 14.6° and 40.8° ± 16.5°, respectively. No significant differences were found in curve progression in left- versus right-sided scoliosis (3.3 ± 7.1 vs 3.7 ± 5.4, = .81), Cobb angle <30° versus ≥30° (2.6 ± 5.0 vs 4.3 ± 6.5, = .30), or when the intercrest line passed through L4 rather than L5 vertebra (3.4 ± 5.0° vs 3.8 ± 7.1°, = .79). No significant differences were found in the sagittal plane between presentation and most recent follow-up.

Conclusions: This is the first study that describes progression in the coronal and sagittal planes in nonsurgical patients with ASD. Previous reported prognostic factors were not confirmed as truly relevant. Although progression appears to occur, large variation exists and these results may not be directly applicable to the individual patient.
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http://dx.doi.org/10.1177/2192568219845659DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7160806PMC
May 2020

Screw-Related Complications After Instrumentation of the Osteoporotic Spine: A Systematic Literature Review With Meta-Analysis.

Global Spine J 2020 Feb 3;10(1):69-88. Epub 2019 Jan 3.

Center for Spine Surgery and Neurotraumatology, Frankfurt, Germany.

Study Design: Systematic literature review with meta-analysis.

Objective: Osteoporosis is common in elderly patients, who frequently suffer from spinal fractures or degenerative diseases and often require surgical treatment with spinal instrumentation. Diminished bone quality impairs primary screw purchase, which may lead to loosening and its sequelae, in the worst case, revision surgery. Information about the incidence of spinal instrumentation-related complications in osteoporotic patients is currently limited to individual reports. We conducted a systematic literature review with the aim of quantifying the incidence of screw loosening in osteoporotic spines.

Methods: Publications on spinal instrumentation of osteoporotic patients reporting screw-related complications were identified in 3 databases. Data on screw loosening and other local complications was collected. Pooled risks of experiencing such complications were estimated with random effects models. Risk of bias in the individual studies was assessed with an adapted McHarm Scale.

Results: From 1831 initial matches, 32 were eligible and 19 reported screw loosening rates. Studies were heterogeneous concerning procedures performed and risk of bias. Screw loosening incidences were variable with a pooled risk of 22.5% (95% CI 10.8%-36.6%, 95% prediction interval [PI] 0%-81.2%) in reports on nonaugmented screws and 2.2% (95% CI 0.0%-7.2%, 95% PI 0%-25.1%) in reports on augmented screws.

Conclusions: The findings of this meta-analysis suggest that screw loosening incidences may be considerably higher in osteoporotic spines than with normal bone mineral density. Screw augmentation may reduce loosening rates; however, this requires confirmation through clinical studies. Standardized reporting of prespecified complications should be enforced by publishers.
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http://dx.doi.org/10.1177/2192568218818164DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6963360PMC
February 2020

Can patient-reported profiles avoid unnecessary referral to a spine surgeon? An observational study to further develop the Nijmegen Decision Tool for Chronic Low Back Pain.

PLoS One 2018 19;13(9):e0203518. Epub 2018 Sep 19.

Department of Orthopaedic Surgery, Radboud University Medical Center, Nijmegen, The Netherlands.

Introduction: Chronic Low Back Pain (CLBP) is a heterogeneous condition with lack of diagnostic clarity. Therapeutic interventions show small effects. To improve outcomes by targeting interventions it is recommended to develop a triage system to surgical and non-surgical treatments based on treatment outcomes. The objective of the current study was to develop and internally validate prognostic models based on pre-treatment patient-reported profiles that identify patients who either respond or do not respond to two frequently performed treatments (lumbar spine surgery and multidisciplinary pain management program).

Methods: A consecutive cohort study in a secondary referral spine center was performed. The study followed the recommendations of the PROGRESS framework and was registered in the Dutch Trial Register (NTR5946). Data of forty-seven potential pre-consultation (baseline) indicators predicting 'response' or 'non-response' at one-year follow-up for the two treatments were obtained to develop and validate four multivariable logistic regression models. The source population consisted of 3,410 referred CLBP-patients. Two treatment cohorts were defined: elective 'spine surgery' (n = 217 [6.4%]) and multidisciplinary bio-psychosocial 'pain management program' (n = 171 [5.0%]). Main inclusion criteria were age ≥18, CLBP (≥6 months), and not responding to primary care treatment. The primary outcome was functional ability: 'response' (Oswestry Disability Index [ODI] ≤22) and 'non-response' (ODI ≥41).

Results: Baseline indicators predictive of treatment outcome were: degree of disability (all models), ≥2 previous spine surgeries, psychosocial complaints, age (onset <20 or >50), and patient expectations of treatment outcomes. The explained variances were low for the models predicting response and non-response to pain management program (R2 respectively 23% and 26%) and modest for surgery (R2 30% and 39%). The overall performance was acceptable (c-index; 0.72-0.83), the model predicting non-response to surgery performed best (R2 = 39%; c-index = 0.83).

Conclusion: This study was the first to identify different patient-reported profiles that predict response to different treatments for CLBP. The model predicting 'non-response' to elective lumbar spine surgery performed remarkably well, suggesting that referrals of these patients to a spine surgeon could be avoided. After external validation, the patient-reported profiles could potentially enhance timely patient triage to the right secondary care specialist and improve decision-making between clinican and patient. This could lead to improved treatment outcomes, which results in a more efficient use of healthcare resources.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0203518PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6145570PMC
February 2019

Does Operative or Nonoperative Treatment Achieve Better Results in A3 and A4 Spinal Fractures Without Neurological Deficit?: Systematic Literature Review With Meta-Analysis.

Global Spine J 2017 Jun 7;7(4):350-372. Epub 2017 Jul 7.

BGU Klinik Frankfurt am Main, Frankfurt, Germany.

Study Design: Systematic literature review with meta-analysis.

Objective: Thoracolumbar (TL) fractures can be treated conservatively or surgically. Especially, the treatment strategy for incomplete and complete TL burst fractures (A3 and A4, AOSpine classification) in neurologically intact patients remains controversial. The aim of this work was to collate the clinical evidence on the respective treatment modalities.

Methods: Searches were performed in PubMed and the Web of Science. Clinical and radiological outcome data were collected. For studies comparing operative with nonoperative treatment, the standardized mean differences (SMD) for disability and pain were calculated and methodological quality and risk of bias were assessed.

Results: From 1929 initial matches, 12 were eligible. Four of these compared surgical with conservative treatment. A comparative analysis of radiological results was not possible due to a lack of uniform reporting. Differences in clinical outcomes at follow-up were small, both between studies and between treatment groups. The SMD was 0.00 (95% CI -0.072, 0.72) for disability and -0.05 (95% CI -0.91, 0.81) for pain. Methodological quality was high in most studies and no evidence of publication bias was revealed.

Conclusions: We did not find differences in disability or pain outcomes between operative and nonoperative treatment of A3 and A4 TL fractures in neurologically intact patients. Notwithstanding, the available scores have been developed and validated for degenerative diseases; thus, their suitability in trauma may be questionable. Specific and uniform outcome parameters need to be defined and enforced for the evaluation of TL trauma.
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http://dx.doi.org/10.1177/2192568217699202DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5546683PMC
June 2017

Which patient-reported factors predict referral to spinal surgery? A cohort study among 4987 chronic low back pain patients.

Eur Spine J 2017 11 30;26(11):2782-2788. Epub 2017 Jun 30.

Department of Health Sciences and EMGO+ Institute for Health and Care Research, Faculty of Earth and Life Sciences, VU University Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands.

Purpose: It is unknown which chronic low back pain (CLBP) patients are typically referred to spinal surgery. The present study, therefore, aimed to explore which patient-reported factors are predictive of spinal surgery referral among CLBP patients.

Methods: CLBP patients were consecutively recruited from a Dutch orthopedic hospital specialized in spine care (n = 4987). The outcome of this study was referral to spinal surgery (yes/no), and was assessed using hospital records. Possible predictive factors were assessed using a screening questionnaire. A prediction model was constructed using logistic regression, with backwards selection and p < 0.10 for keeping variables in the model. The model was internally validated and evaluated using discrimination and calibration measures.

Results: Female gender, previous back surgery, high intensity leg pain, somatization, and positive treatment expectations increased the odds of being referred to spinal surgery, while being obese, having comorbidities, pain in the thoracic spine, increased walking distance, and consultation location decreased the odds. The model's fit was good (X  = 10.5; p = 0.23), its discriminative ability was poor (AUC = 0.671), and its explained variance was low (5.5%). A post hoc analysis indicated that consultation location was significantly associated with spinal surgery referral, even after correcting for case-mix variables.

Conclusion: Some patient-reported factors could be identified that are predictive of spinal surgery referral. Although the identified factors are known as common predictive factors of surgery outcome, they could only partly predict spinal surgery referral.
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http://dx.doi.org/10.1007/s00586-017-5201-9DOI Listing
November 2017

Computational anatomy of the dens axis evaluated by quantitative computed tomography: Implications for anterior screw fixation.

J Orthop Res 2017 10 30;35(10):2154-2163. Epub 2017 Jan 30.

AO Research Institute Davos, Clavadelerstrasse 8, 7270 Davos, Switzerland.

The surgical fracture fixation of the odontoid process (dens) of the second cervical vertebra (C2/axis) is a challenging procedure, particularly in elderly patients affected by bone loss, and includes screw positioning close to vital structures. The aim of this study was to provide an extended anatomical knowledge of C2, the bone mass distribution and bone loss, and to understand the implications for anterior screw fixation. One hundred and twenty standard clinical quantitative computed tomography (QCT) scans of the intact cervical spine from 60 female and 60 male European patients, aged 18-90 years, were used to compute a three-dimensional statistical model and an averaged bone mass model of C2. Shape and size variability was assessed via principal component analysis (PCA), bone mass distribution by thresholding and via virtual core drilling, and the screw placement via virtual positioning of screw templates. Principal component analysis (PCA) revealed a highly variable anatomy of the dens with size as the predominant variation according to the first principal component (PC) whereas shape changes were primarily described by the remaining PCs. The bone mass distribution demonstrated a characteristic 3D pattern, and remained unchanged in the presence of bone loss. Virtual screw positioning of two 3.5 mm dens screws with a 1 mm safety zone was possible in 81.7% in a standard, parallel position and in additional 15.8% in a twisted position. The approach permitted a more detailed anatomical assessment of the dens axis. Combined with a preoperative QCT it may further improve the diagnostic procedure of odontoid fractures. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2154-2163, 2017.
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http://dx.doi.org/10.1002/jor.23512DOI Listing
October 2017

Current Construct Options for Revision of Large Acetabular Defects: A Systematic Review.

JBJS Rev 2016 11;4(11)

1Department of Orthopaedic Surgery, Sint Maartenskliniek, Nijmegen, the Netherlands.

Background: Many treatment options are available for the revision of large acetabular defects. Debate continues as to which technique is most effective.

Methods: A systematic review was performed according to the Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines to evaluate the effectiveness of interventions for large acetabular defects. Quality assessment was performed next with use of 8 items of the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) checklist for reports of observational studies. Large acetabular defects were defined as American Academy of Orthopaedic Surgeons (AAOS) type III or IV or Paprosky type 3A or 3B. Outcomes included re-revision, radiographic loosening, complications, and clinical outcomes.

Results: We found 7 different treatment options for large acetabular defects in 20 included studies: antiprotrusio cage (8 studies), Trabecular Metal (Zimmer) augment and shell (4 studies), bone impaction grafting with a metal mesh (2 studies), hemispherical implant with hook and flanges (2 studies), Trabecular Metal augment or structural allograft with cup (2 studies), cup-cage reconstruction (1 study), and custom-made triflange component (1 study).

Conclusions: Trabecular Metal augments and shells gave the most promising results in terms of the re-revision rate and radiographic loosening. Reconstruction with an antiprotrusio cage was the most frequently reported technique, with good results in a physically low-demand elderly population. Bone impaction grafting seems not appropriate for pelvic discontinuity and prone to failure in patients with Paprosky type-3B defects. In those cases, a custom-made triflange implant or a cup-cage reconstruction might be the best alternative, but few reports of sufficient quality are available yet.

Level Of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
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http://dx.doi.org/10.2106/JBJS.RVW.15.00119DOI Listing
November 2016

Kinematic Magnetic Resonance Imaging Assessment of the Degenerative Cervical Spine: Changes after Anterior Decompression and Cage Fusion.

Global Spine J 2016 Nov 23;6(7):673-678. Epub 2016 Feb 23.

Department of Orthopedics, Sint Maartenskliniek, Nijmegen, The Netherlands.

 A prospective cohort study.  Decompression and fusion of cervical vertebrae is a combined procedure that has a high success rate in relieving radicular symptoms and stabilizing or improving cervical myelopathy. However, fusion may lead to increased motion of the adjacent vertebrae and cervical deformity. Both have been postulated to lead to adjacent segment pathology (ASP). Kinematic magnetic resonance imaging (MRI) has been increasingly used to evaluate range of motion (ROM) of the cervical spine and ASP. Our objective was to measure ASP, cervical curvature, and ROM of individual segments of the cervical spine using kinematic MRI before and 24 months after monosegmental cage fusion.  Eighteen patients who had single-level interbody fusion were included. ROM (using kinematic MRI) and degeneration, spinal stenosis, and cervical curvature were measured preoperatively and 24 months postoperatively.  Using kinematic MRI, segmental motion of the cervical segments was measured with a precision of less than 3 degrees. The cervical fusion did not affect the ROM of adjacent levels. However, pre- and postoperative ROM was higher at the levels immediately adjacent to the fusion level compared with those further away. In addition, at 24 months postoperatively, the number of cases with ASP was higher at the levels immediately adjacent to fusion level.  Using kinematic MRI, ROM after spinal fusion can be measured with high precision. Kinematic MRI can be used not only in clinical practice, but also to study intervention and its effect on postoperative biomechanics and ASP of cervical vertebrae.
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http://dx.doi.org/10.1055/s-0036-1579551DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5077714PMC
November 2016

Cancellous and cortical bone mineral density around an elastic press-fit socket in total hip arthroplasty.

Acta Orthop 2016 Dec 23;87(6):583-588. Epub 2016 Sep 23.

a Department of Orthopaedic surgery , Sint Maartenskliniek.

Background and purpose - The acetabular component has remained the weakest link in hip arthroplasty for achievement of long-term survival. One of the possible explanatory factors for acetabular failure has been acetabular stress shielding. For this, we investigated the effects of a cementless elastic socket on acetabular bone mineral density (BMD). Patients and methods - During 2008-2009, we performed a single-center prospective cohort trial on 25 patients (mean age 64 (SD 4), 18 females) in whom we implanted a cementless elastic press-fit socket. Using quantitative BMD measurements on CT, we determined the change in BMD surrounding the acetabular component over a 2-year follow-up period. Results - We found a statistically significant decrease in cancellous BMD (-14% to -35%) and a stable level of cortical BMD (5% to -5%) surrounding the elastic press-fit cup during the follow-up period. The main decrease was seen during the first 6 months after implantation. During the second year, cancellous BMD showed a further decrease in the medial and lower acetabular regions. Interpretation - We found no evidence that an elastic press-fit socket would prevent acetabular stress shielding during a 2-year follow-up.
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http://dx.doi.org/10.1080/17453674.2016.1237439DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5119440PMC
December 2016

A Custom-made Acetabular Implant for Paprosky Type 3 Defects.

Orthopedics 2017 Jan 9;40(1):e195-e198. Epub 2016 Sep 9.

Acetabular revision is a challenging operation, especially when dealing with major bone loss and poor bone quality. This article describes a detailed approach to defect analysis, including measurement of bone deficiency and bone quality. A custom-made titanium implant, with precisely outlined flanges to the host bones of the ilium, ischium, and pubis, taking into account the bone quality for optimal screw purchase, was used to reconstruct the acetabular defect. Preliminary results for 12 patients who were retrospectively reviewed after a minimum follow-up of 18 months were promising. [Orthopedics. 2017; 40(1):e195-e198.].
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http://dx.doi.org/10.3928/01477447-20160902-01DOI Listing
January 2017

No effect of additional screw fixation of a cementless, all-polyethylene press-fit socket on migration, wear, and clinical outcome.

Acta Orthop 2016 Aug 14;87(4):363-7. Epub 2016 Jun 14.

b Department of Orthopedics , Sint Maartenskliniek , Nijmegen , the Netherlands .

Background and purpose - Additional screw fixation of the all-polyethylene press-fit RM cup (Mathys) has no additional value for migration, in the first 2 years after surgery. However, the medium-term and long-term effects of screw fixation remain unclear. We therefore evaluated the influence of screw fixation on migration, wear, and clinical outcome at 6.5 years using radiostereometric analysis (RSA). Patients and methods - This study involved prolonged follow-up from a previous randomized controlled trial (RCT). We analyzed RSA radiographs taken at baseline and at 1-, 2-, and 6.5-year follow-up. Cup migration and wear were assessed using model-based RSA software. Wear was calculated as translation of the femoral head model in relation to the cup model. Total translation, rotation, and wear were calculated mathematically from results of the orthogonal components. Results - 27 patients (15 with screw fixation and 12 without) were available for follow-up at 6.5 (5.6-7.2) years. Total translation (0.50 mm vs. 0.56 mm) and rotation (1.01 degrees vs. 1.33 degrees) of the cup was low, and was not significantly different between the 2 groups. Wear increased over time, and was similar between the 2 groups (0.58 mm vs. 0.53 mm). Wear rate (0.08 mm/year vs. 0.09 mm/year) and clinical outcomes were also similar. Interpretation - Our results indicate that additional screw fixation of all-polyethylene press-fit RM cups has no additional value regarding medium-term migration and clinical outcome. The wear rate was low in both groups.
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http://dx.doi.org/10.1080/17453674.2016.1190244DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4967278PMC
August 2016

Multimodality intraoperative neuromonitoring in extreme lateral interbody fusion. Transcranial electrical stimulation as indispensable rearview.

Eur Spine J 2016 05 27;25(5):1581-1586. Epub 2015 Aug 27.

Department of Orthopedics, Sint Maartenskliniek, Nijmegen, The Netherlands.

Purpose: To optimize intraoperative neuromonitoring during extreme lateral interbody fusion (XLIF) by adding transcranial electrical stimulation with motor evoked potential (TESMEP) to previously described monitoring using spontaneous EMG (sEMG) and peripheral stimulation (triggered EMG: tEMG).

Methods: Twenty-three patients with degenerative lumbar scoliosis had XLIF procedures and were monitored using sEMG, tEMG and TESMEP. Spontaneous and triggered muscle activity, and the MEP of 5 ipsilateral leg muscles, 2 contralateral leg muscles and 1 arm muscle were monitored.

Results: During XLIF surgery decreased MEP amplitudes were measured in 9 patients and in 6 patients sEMG was documented. In 4 patients, both events were described. In 30 % of the cases (n = 7), the MEP amplitude decreased immediately after breaking of the table and even before skin incision. After reduction of the table break, the MEP amplitudes recovered to baseline. In two patients, the MEP amplitude deteriorated during distraction of the psoas with the retractor, while no events were reported using sEMG and tEMG. Repositioning of the retractor led to recovery of the MEP.

Conclusions: Monitoring the complete nervous system during an XLIF procedure is found to be helpful since nerve roots, lumbar plexus as well as the intradural neural structures may be at risk. TESMEP has additional value to sEMG and tEMG during XLIF procedure: (1) it informed about otherwise unnoticed events, and (2) it confirmed and added information to events measured using sEMG.
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http://dx.doi.org/10.1007/s00586-015-4182-9DOI Listing
May 2016

The Oswestry Disability Index (version 2.1a): validation of a Dutch language version.

Spine (Phila Pa 1976) 2015 Jan;40(2):E83-90

*Departments of Research and †Orthopedics, Sint Maartenskliniek, GM Nijmegen, The Netherlands ‡Nuffield Department of Orthopaedics, Rheumatology, and Musculoskeletal Science, University of Oxford, Nuffield Orthopaedic Centre, Oxford, United Kingdom §Achmea Health Insurance Company, AW Zeist, The Netherlands; and ¶Department of Neurosurgery, Leiden University Medical Center, RC Leiden, The Netherlands.

Study Design: A cross-sectional study on baseline data.

Objective: To translate the Oswestry Disability Index (ODI) version 2.1a into the Dutch language and to validate its use in a cohort of patients with chronic low back pain in secondary spine care.

Summary Of Background Data: Patient-reported outcome measures (PROMs) are commonly accepted to evaluate the outcome of spine interventions. Functional status is an important outcome in spine research. The ODI is a recommended condition-specific patient-reported outcome measure used to evaluate functional status in patients with back pain. As yet, no formal translated Dutch version exists.

Methods: The ODI was translated according to established guidelines. The final version was built into the electronic web-based system in addition with the Roland Morris Disability Questionnaire, the numeric rating scale for pain severity, 36-Item Short Form Health Survey Questionnaire for quality of life, and the hospital anxiety and depression scale. Baseline data were used of 244 patients with chronic low back pain who participated in a combined physical and psychological program. Floor and ceiling effects, internal consistency, and the construct validity were evaluated using quality criteria.

Results: The mean ODI (standard deviation) was 39.6 (12.3); minimum 6, maximum 70. Most of the participants (88%) were moderately to severely disabled. Factor analysis determined a 1-factor structure (36% explained variance) and the homogeneity of ODI items is shown (Cronbach α = 0.79). The construct validity is supported as all (6:6) the a priori hypotheses were confirmed. Moreover, the ODI and Roland Morris Disability Questionnaire, showed a strong significant correlation (r = 0.68, P < 0.001) and an overlap: mean difference of -18 (95% limits of agreement: -44 to 8).

Conclusion: The Dutch ODI version 2.1a is a valid and valuable tool for the measurement of functional status and disability among Dutch patients with chronic low back pain. This translated condition-specific patient-reported outcome measure version is recommended for use in future back pain research and to evaluate outcome of back care in the Netherlands.
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http://dx.doi.org/10.1097/BRS.0000000000000683DOI Listing
January 2015

Alternative Surgical Strategy for AxiaLIF Pseudarthrosis: A Series of Three Case Reports.

Evid Based Spine Care J 2013 Oct;4(2):143-8

Department of Orthopaedic Surgery, Sint Maartenskliniek, Nijmegen, The Netherlands.

Study Design Retrospective case series. Objective The objective of this study is to describe an alternative technique to attain interbody lumbar fusion in the event of pseudarthrosis after axial lumbar interbody fusion (AxiaLIF) and to assess its safety. Methods Three patients who suffered from pseudarthrosis after AxiaLIF underwent revision surgery with a DEVEX cage (DePuy Synthes, Raynham, MA, United States) through an anterior approach. We report technical details as well as clinical and radiological results at 12 months follow-up. Results Preoperative symptoms resolved in all cases. There were no perioperative complications. One patient had a deep venous thrombosis at postoperative day 9. A decrease in visual analog scale score for pain was observed, from 8.67 preoperatively to 2 postoperatively at final follow-up. Radiographic workup after 12 months showed no sign of implant failure or loosening, and fusion was obtained in all cases. Conclusion Anterior fusion with a DEVEX cage in front of a TranS1 screw (TranS1 screw, Inc., Wilmington, North Carolina, United States) for AxiaLIF pseudarthrosis is safe and effective.
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http://dx.doi.org/10.1055/s-0033-1357357DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3836895PMC
October 2013

Predictive factors for successful clinical outcome 1 year after an intensive combined physical and psychological programme for chronic low back pain.

Eur Spine J 2014 Jan 16;23(1):102-12. Epub 2013 Jun 16.

Sint Maartenskliniek, P.O. Box 9011, 6500 GM, Nijmegen, The Netherlands,

Purpose: The aim of this longitudinal study is to determine the factors which predict a successful 1-year outcome from an intensive combined physical and psychological (CPP) programme in chronic low back pain (CLBP) patients.

Methods: A prospective cohort of 524 selected consecutive CLBP patients was followed. Potential predictive factors included demographic characteristics, disability, pain and cognitive behavioural factors as measured at pre-treatment assessment. The primary outcome measure was the oswestry disability index (ODI). A successful 1-year follow-up outcome was defined as a functional status equivalent to 'normal' and healthy populations (ODI ≤22). The 2-week residential programme fulfills the recommendations in international guidelines. For statistical analysis we divided the database into two equal samples. A random sample was used to develop a prediction model with multivariate logistic regression. The remaining cases were used to validate this model.

Results: The final predictive model suggested being 'in employment' at pre-treatment [OR 3.61 (95 % CI 1.80-7.26)] and an initial 'disability score' [OR 0.94 (95 % CI 0.92-0.97)] as significant predictive factors for a successful 1-year outcome (R (2) = 22 %; 67 % correctly classified). There was no predictive value from measures of psychological distress.

Conclusion: CLBP patients who are in work and mild to moderately disabled at the start of a CPP programme are most likely to benefit from it and to have a successful treatment outcome. In these patients, the disability score falls to values seen in healthy populations. This small set of factors is easily identified, allowing selection for programme entry and triage to alternative treatment regimes.
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http://dx.doi.org/10.1007/s00586-013-2844-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3897840PMC
January 2014

A cementless, elastic press-fit socket with and without screws.

Acta Orthop 2012 Oct;83(5):481-7

Department Orthopaedic and Trauma Surgery, Orthopaedic Centre OCON, Hengelo, the Netherlands.

Background: The acetabular component has remained the weakest link in hip arthroplasty regarding achievement of long-term survival. Primary fixation is a prerequisite for long-term performance. For this reason, we investigated the stability of a unique cementless titanium-coated elastic monoblock socket and the influence of supplementary screw fixation.

Patient And Methods: During 2006-2008, we performed a randomized controlled trial on 37 patients (mean age 63 years (SD 7), 22 females) in whom we implanted a cementless press-fit socket. The socket was implanted with additional screw fixation (group A, n = 19) and without additional screw fixation (group B, n = 18). Using radiostereometric analysis with a 2-year follow-up, we determined the stability of the socket. Clinically relevant migration was defined as > 1 mm translation and > 2º rotation. Clinical scores were determined.

Results: The sockets without screw fixation showed a statistically significantly higher proximal translation compared to the socket with additional screw fixation. However, this higher migration was below the clinically relevant threshold. The numbers of migratory sockets were not significantly different between groups. After the 2-year follow-up, there were no clinically relevant differences between groups A and B regarding the clinical scores. 1 patient dropped out of the study. In the others, no sockets were revised.

Interpretation: We found that additional screw fixation is not necessary to achieve stability of the cementless press-fit elastic RM socket. We saw no postoperative benefit or clinical effect of additional screw fixation.
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http://dx.doi.org/10.3109/17453674.2012.720116DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3488174PMC
October 2012

Is there evidence for a superior method of socket fixation in hip arthroplasty? A systematic review.

Int Orthop 2011 Aug 15;35(8):1109-18. Epub 2011 Mar 15.

Department of Orthopaedic Surgery, Medisch Spectrum Twente, P.O. Box 50000 , 7500, KA Enschede, The Netherlands.

Purpose: Total hip arthroplasty has been a very succesful orthopaedic procedure. The optimal fixation method of the acetabular component however, has not yet been defined.

Methods: We performed a systematic review using the Medline and Embase databases to find evidence for the superiority of cemented or cementless acetabular components on short- and long-term clinical and radiological parameters. Methodological quality for randomised trials was assessed using the van Tulder checklist, and for the non randomised studies we used the Newcastle-Ottawa quality assessment scale.

Results: Our search strategy revealed 16 randomised controlled trials (RCT) and 19 non RCT studies in which cemented and cementless acetabular components are compared. A best evidence analysis for complications, wear, osteolysis, migration and clinical scores showed no superiority for either cemented or cementless socket in the RCTs. A best evidence analysis for non RCT studies revealed better osteolysis, migration properties and aseptic loosening survival for cementless sockets; however, wear and overall survival favoured the cemented sockets.

Conclusions: We recommend that an orthopaedic surgeon should choose an established cemented or cementless socket for hip replacement based on patient characteristics, knowledge, experience and preference.
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http://dx.doi.org/10.1007/s00264-011-1234-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3167434PMC
August 2011

A cementless elastic monoblock socket in young patients: a ten to 18-year clinical and radiological follow-up.

Int Orthop 2011 Oct 5;35(10):1445-51. Epub 2010 Sep 5.

Department of Orthopaedic Surgery, St. Maartenskliniek Hospital, P.O. Box 9011, 6500 GM, Nijmegen, The Netherlands.

The survival of acetabular components depends on several factors: wear, osteolysis and septic or aseptic loosening. Osteolysis seems to be the main cause for concern in cementless arthroplasties. Acetabular osteolysis results from particle debris and segmental unloading of acetabular bone by rigid sockets. We investigated a cementless elastic monoblock socket with regard to acetabular osteolysis and aseptic loosening in a cohort of young patients. We evaluated 158 hip arthroplasties with a minimum follow-up of ten years (ten to 18) and a mean age of 42 years (18-50). The overall revision rate at 14 years was 80% with a 98% survival rate for aseptic loosening. The mean polyethylene wear rate was 0.11 mm/year. Progressive acetabular osteolysis was seen in 3% of patients evaluated. In conclusion, we found low pelvic osteolysis rates, acceptable overall wear rates, satisfactory overall survival and excellent survival rates for aseptic loosening of a cementless elastic monoblock socket in patients younger than 50 years. Ongoing tribology developments and knowledge about acetabular bone adaptations behind acetabular implants will further lower wear and osteolysis rates and optimise survival rates of cementless sockets.
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http://dx.doi.org/10.1007/s00264-010-1120-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3174288PMC
October 2011

Daily functioning and self-management in patients with chronic low back pain after an intensive cognitive behavioral programme for pain management.

Eur Spine J 2010 Sep 27;19(9):1517-26. Epub 2010 May 27.

Department Research Development and Education, Sint Maartenskliniek, PO Box 9011, 6500 GM Nijmegen, The Netherlands.

Chronic low back pain (CLBP) is associated with persistent or recurrent disability which results in high costs for society. Cognitive behavioral treatments produce clinically relevant benefits for patients with CLBP. Nevertheless, no clear evidence for the most appropriate intervention is yet available. The purpose of this study is to evaluate the mid-term effects of treatment in a cohort of patients with CLBP participating in an intensive pain management programme. The programme provided by RealHealth-Netherlands is based on cognitive behavioral principles and executed in collaboration with orthopedic surgeons. Main outcome parameters were daily functioning (Roland and Morris Disability Questionnaire and Oswestry Disability Questionnaire), self-efficacy (Pain Self-Efficacy Questionnaire) and quality of life (Short Form 36 Physical Component Score). All parameters were measured at baseline, last day of residential programme and at 1 and 12 months follow-up. Repeated measures analysis was applied to examine changes over time. Clinical relevance was examined using minimal clinical important differences (MCID) estimates for main outcomes. To compare results with literature effect sizes (Cohen's d) and Standardized Morbidity Ratios (SMR) were determined. 107 patients with CLBP participated in this programme. Mean scores on outcome measures showed a similar pattern: improvement after residential programme and maintenance of results over time. Effect sizes were 0.9 for functioning, 0.8 for self-efficacy and 1.3 for physical functioning related quality of life. Clinical relevancy: 79% reached MCID on functioning, 53% on self-efficacy and 80% on quality of life. Study results on functioning were found to be 36% better and 2% worse when related to previous research on, respectively, rehabilitation programmes and spinal surgery for similar conditions (SMR 136 and 98%, respectively). The participants of this evidence-based programme learned to manage CLBP, improved in daily functioning and quality of life. The study results are meaningful and comparable with results of spinal surgery and even better than results from less intensive rehabilitation programmes.
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http://dx.doi.org/10.1007/s00586-010-1435-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2989287PMC
September 2010

Anterior cervical interbody fusion with a titanium box cage: early radiological assessment of fusion and subsidence.

Spine J 2005 Nov-Dec;5(6):645-9; discussion 649

Institute of Spinal Surgery and Applied Research, Sint Maartenskliniek, Hengstdal 3, 6522 JV Nijmegen, The Netherlands.

Background Context: The use of stand-alone cervical interbody cages in anterior cervical discectomy with fusion (ACDF) has become popular, but high subsidence rates have been reported in the literature.

Purpose: The authors present short-term radiological results of a titanium box cage with regard to fusion and subsidence. Reliable fusion and lack of subsidence may influence long-term clinical results. Early radiological data are necessary before implementation of this device on a larger scale can be accepted.

Study Design/setting: Retrospective radiological quality assessment study.

Patient Sample: ACDF using the titanium cage was performed in 71 consecutive patients at 106 levels. Diagnoses included cervical disc disease (57) and cervical spinal stenosis (14) after failed conservative treatment.

Outcome Measures: Subsidence and kyphosis were assessed on lateral cervical radiographs made directly postoperative and at 3- and 6-month follow-up. At 6-month follow-up, lateral flexion-extension radiographs were made to assess fusion.

Methods: Subsidence of the cage was defined as a decrease in total vertical height of the two fused vertebral bodies as measured on the lateral cervical radiographs made 3 and 6 months postoperatively compared with the directly postoperative radiographs. Segmental kyphosis was measured as the angle between the posterior borders of the two vertebral bodies on the lateral radiograph.

Results: No patients were lost to follow-up. Fusion was achieved after 6 months in all patients. At 3 and 6 months postoperative the same 10 cages (each in a different patient) had subsided. The C6-C7 level was significantly more frequently involved compared with all other levels. A segmental kyphotic alignment was observed in five patients at the C6-C7 level and in one patient at the C4-C5 level.

Conclusions: For patients with cervical disc disease, the high subsidence tendency of the cage into the end plate of predominantly C7 is a disturbing phenomenon found in this study. A modified cage design that improves and extends contact with the inferior surface could be expected to reduce subsidence into C7.
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http://dx.doi.org/10.1016/j.spinee.2005.07.007DOI Listing
February 2006

Congenital cataract facial dysmorphism neuropathy syndrome: a clinically recognizable entity.

Pediatr Neurol 2005 Oct;33(4):277-9

Department of Paediatric Neurology, University Medical Centre Nijmegen, Nijmegen, The Netherlands.

Congenital cataracts facial dysmorphism neuropathy syndrome is a recently delineated autosomal recessive condition exclusively found in the Gypsy population. Congenital cataracts facial dysmorphism neuropathy syndrome is caused by a homozygous mutation in the CTDP1 gene, leading to disruption of the ribonucleic acid transcription machinery. This report presents a young Gypsy female affected by this rare disorder. Electromyography and sural nerve histology were in accordance with a hypomyelinating neuropathy. After clinical recognition of congenital cataracts facial dysmorphism neuropathy syndrome some years ago, we recently demonstrated the presence of the homozygous IVS6+389C-->T mutation in the CTDP1 gene in this family.
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http://dx.doi.org/10.1016/j.pediatrneurol.2005.04.011DOI Listing
October 2005

How close does an uncemented hip stem match the final rasp position?

Acta Orthop Belg 2004 Dec;70(6):534-9

Orthopaedic Research Laboratory, University Medical Centre Nijmegen, Nijmegen, The Netherlands.

During total hip arthroplasty the final clinical position of the cementless CLS stem (Centerpulse) is not always identical to the position of the final rasp with which a successful trial reduction was performed. Therefore, the rasp-stem correspondence of CLS system (Centerpulse) was investigated in a laboratory study and compared to the CBC-T system (Mathys). Both systems showed an average rasp-stem mismatch below 2 mm in three orthogonal directions. It was found that this mismatch related to geometric differences at the corners between rasp and stem. The measured mismatch is not expected to have adverse clinical consequences.
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December 2004

Prophylaxis for heterotopic ossification after primary total hip arthroplasty. A cohort study between indomethacin and meloxicam.

Acta Orthop Belg 2004 Jun;70(3):240-6

Department of Orthopaedics, Sint Maartenskliniek, Nijmegen, The Netherlands.

The authors have conducted a prospective cohort study of the efficacy of a 7 days administration of Indomethacin (n = 89) versus Meloxicam (n = 92), in the prophylaxis of heterotopic ossification (HO) in primary total hip arthroplasty. To assess the interobserver variability of the Brooker classification, all radiographs were evaluated by three investigators. In the Indomethacin group 25 patients developed HO (grade I: 22, grade III: 2 and grade IV: 1). In the Meloxicam group 34 developed HO (grade I: 30, grade II: 1 and grade III: 3). We were not able to show any difference between Indomethacin and Meloxicam in preventing heterotopic ossification after primary hip arthroplasty. We found a high interobserver variability in the grading system according to Brooker, in particular for the higher grades(grade II, III and IV).
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June 2004